1. Field of the Invention
The present invention relates to an intake structure for a fuel cell in a fuel cell powered vehicle, and a motorcycle with a fuel cell mounted thereon to which the structure is applied.
2. Description of Background Art
Conventionally, as an intake system in a fuel cell powered vehicle, there has been a system in which air (oxidizer gas) supercharged by a supercharger is supplied to a fuel cell after being humidified by a humidifier. The exhaust gas from the fuel cell is returned to the humidifier, where moisture is extracted, and new intake air to be supplied to the fuel cell is humidified with the extracted moisture. In this instance, if the humidifier is cooled excessively, the degree of saturation of the water vapor is so lowered that it becomes difficult to extract the moisture. In view of this, there has been a system in which a heat medium (cooling water) having been used for cooling the fuel cell is circulated around the humidifier for the purpose of warming the humidifier (see, for example, Japanese Patent Laid-open No. 2001-216981.)
In the conventional configurations as above-mentioned, however, it is necessary to set warming members such as a water jacket and a water pump for circulating the cooling water around the humidifier, which may lead to increases in the cost and weight of the vehicle. Therefore, there is a demand for improving these points.
In addition, in some conventional systems, a bypass valve is provided for changing over an intake line for permitting the compressed air to bypass the humidifier at a low temperature time such as a starting time of the fuel cell (see, for example, Japanese Patent Laid open No. 2004 152600.)
Meanwhile, in the intake system of the fuel cell powered vehicle as above, it is necessary to arrange many intake system members such as a supercharger, a bypass valve, and a humidifier. Particularly in consideration of the case where the vehicle is of a small type, as in the case of a motorcycle, it is desirable that the intake system members can be arranged efficiently in a small layout space and that a pressure loss in the intake system is suppressed.